Method of manufacturing terminal-formed electric wire

ABSTRACT

A method of manufacturing a terminal-formed electric wire includes a welding member placing process in which at least one welding member formed of metal having a melting point lower than that of a plurality of metal strands included in a core wire is arranged to the core wire of at least a terminal-forming target portion of the electric wire, and a terminal forming process in which the exposed terminal-forming target portion is interposed between first and second electrodes having a shape corresponding to a desired terminal shape, at least the welding member in the terminal-forming target portion is melted by electrically conducting the first and second electrodes while pressing the terminal-forming target portion with the first and second electrodes, and the melted metal is then solidified, so that the terminal-forming target portion is formed as a terminal portion having a desired terminal shape.

CROSS-REFERENCE TO RELATED APPLICATION (S)

The present application claims priority to and incorporates by referencethe entire contents of Japanese Patent Application No. 2016-101950 filedin Japan on May 20, 2016.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method of manufacturing aterminal-formed electric wire.

2. Description of the Related Art

There is conventionally known a technique relating to a so-calledterminal-formed electric wire in which, instead a terminal metal fittinginstalled in an electric wire, a part of a core wire of the electricwire is formed in a desired terminal shape. In this technique, forexample, the core wire is exposed by stripping off a covering of theelectric wire, and a terminal-forming target portion of this exposedportion is interposed between a pair of electrodes. In addition, thepair of electrodes are electrically conducted while pressing theterminal-forming target portion with the pair of electrodes. As aresult, the core wire of the terminal-forming target portion is meltedunder pressing and heating. Then, in this technique, the electricconduction to the pair of electrodes is stopped, and the core wire iscooled while maintaining the pressed state, so that solidification ofthe melted core wire is waited. Here, the pair of electrodes are formedin a shape corresponding to a desired terminal shape. As a result, theterminal-forming target portion is formed in a desired terminal shape.The terminal-formed electric wire in this type is disclosed in, forexample, Japanese Patent Application Laid-Open No. 04-249875.

However, in order to execute terminal forming of the core wire, it isnecessary to heat the core wire up to a temperature higher than amelting point of the core wire. For this reason, depending on themelting point, the core wire may not be perfectly melted, and thereforethere is a possibility that it is difficult to form the desired terminalshape.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method ofmanufacturing a terminal-formed electric wire, capable of executingdesired terminal forming.

In order to achieve the above mentioned object, a method ofmanufacturing a terminal-formed electric wire according to one aspect ofthe present invention includes a welding member placing process in whichat least one welding member formed of metal having a melting point lowerthan that of a plurality of metal strands included in a core wire isarranged to the core wire of at least a terminal-forming target portionof an electric wire; and a terminal forming process in which the exposedterminal-forming target portion is interposed between a pair ofelectrodes having a shape corresponding to a desired terminal shape, atleast the welding member in the terminal-forming target portion ismelted by electrically conducting the pair of electrodes while pressingthe terminal-forming target portion with the pair of electrodes, andmelted metal is solidified by stopping electric conduction to the pairof electrodes. Consequently, the terminal-forming target portion isformed as a terminal portion having the terminal shape.

According to another aspect of the present invention, in the weldingmember placing process, the welding member may be arranged to interposethe core wire.

According to still another aspect of the present invention, the methodmay further include a strand dividing process in which the plurality ofstrands of the terminal-forming target portion are divided into aplurality of strand groups, wherein in the welding member placingprocess, the strand groups and welding members are arranged alternately.

According to still another aspect of the present invention, in thewelding member placing process, the welding member may be insertedbetween the plurality of strands.

According to still another aspect of the present invention, in thewelding member placing process, the welding member may be wound aroundthe core wire.

According to still another aspect of the present invention, in thewelding member placing process, a powder-like welding member may beapplied to the core wire.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a terminal portion of aterminal-formed electric wire;

FIG. 2 is a perspective view illustrating a terminal-forming targetportion of an electric wire;

FIG. 3 is a perspective view illustrating a ring-shaped terminal-formingtarget portion of a temporary shape and a welding member according to anembodiment before placing the welding member;

FIG. 4 is a flowchart illustrating a main process in the method ofmanufacturing the terminal-formed electric wire;

FIG. 5 is a perspective view illustrating a molding die in a pre-moldingprocess;

FIG. 6 is a partial cross-sectional view illustrating a portion fordescribing the pre-molding process;

FIG. 7 is a perspective view illustrating a shape of the welding memberand placement of the welding member relative to the ring-shapedterminal-forming target portion of the temporary shape according to anembodiment;

FIG. 8 is a perspective view illustrating a pair of electrodes used inthe terminal forming process before pressing;

FIG. 9 is a perspective view illustrating the pair of electrodes used inthe terminal forming process in a pressed state;

FIG. 10 is a cross-sectional view illustrating the pair of electrodesused in the terminal forming process in a pressed state;

FIG. 11 is a cross-sectional view illustrating the pair of electrodesused in the terminal forming process after the terminal forming iscompleted;

FIG. 12 is a perspective view illustrating the ring-shapedterminal-forming target portion of the temporary shape according to afirst modification;

FIG. 13 is a side view illustrating an example of the placement of thewelding member relative to the ring-shaped terminal-forming targetportion of the temporary shape according to the first modification;

FIG. 14 is a side view illustrating another example of the placement ofthe welding member relative to the ring-shaped terminal-forming targetportion of the temporary shape according to the first modification;

FIG. 15 is a side view illustrating another example of the placement ofthe welding member relative to the ring-shaped terminal-forming targetportion of the temporary shape according to the first modification;

FIG. 16 is a perspective view illustrating a shape of the welding memberand the placement of the welding member relative to the core wireaccording to a second modification;

FIG. 17 is a perspective view illustrating a shape of the welding memberand the placement of the welding member relative to the terminal-formingtarget portion according to the second modification;

FIG. 18 is a perspective view illustrating another shape of the weldingmember according to the second modification;

FIG. 19 is a perspective view illustrating an example of the placementof the welding member relative to the ring-shaped terminal-formingtarget portion of the temporary shape according to the secondmodification;

FIG. 20 is a perspective view illustrating a welding member according toa third modification;

FIG. 21 is a perspective view illustrating an example of the placementof the welding member relative to the terminal-forming target portionaccording to the third modification;

FIG. 22 is a perspective view illustrating an example of the placementof the welding member relative to the ring-shaped terminal-formingtarget portion of the temporary shape according to the thirdmodification;

FIG. 23 is a perspective view illustrating a welding member according toa fourth modification; and

FIG. 24 is a perspective view illustrating an example of the placementof the welding member relative to the ring-shaped terminal-formingtarget portion of the temporary shape according to the fourthmodification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A method of manufacturing a terminal-formed electric wire according toan embodiment of the present invention will be described in detail withreference to the accompanying drawings. Note that the present inventionis not limited to this embodiment.

Embodiment

One embodiment regarding a method of manufacturing a terminal-formedelectric wire according to the present invention will be described withreference to FIGS. 1 to 24.

A method of manufacturing the terminal-formed electric wire according tothe embodiment is to form a so-called terminal-formed electric wire 100A(FIG. 1) in which a part of a core wire 110 of an electric wire 100 isformed in a desired terminal shape. In the method of manufacturing theterminal-formed electric wire, a terminal-forming target portion 130 isformed as a terminal portion 130A (FIG. 1) having a desired terminalshape by melting and solidifying the terminal-forming target portion 130(FIG. 2) in an exposed portion of the core wire (a portion where nocovering 120 is provided) of the electric wire 100. In the method ofmanufacturing the terminal-formed electric wire according to theembodiment, it is assumed that the core wire 110 is formed from aplurality of metal strands 110 a. This core wire 110 may be formed bysimply binding a plurality of strands 110 a or may be a twisted wireformed by twisting a plurality of bound strands 110 a. In addition, theexposed portion of the core wire of the electric wire 100 may be aportion formed by stripping off the covering 120 that covers the corewire 110 after manufacturing of the electric wire 100 or may be aportion where the covering 120 is not formed during manufacturing of theelectric wire 100 through masking or the like. Furthermore, the terminalportion 130A may have any shape such as an eyelets type or a flat typeas long as it can be formed.

The method of manufacturing the terminal-formed electric wire accordingto the embodiment at least includes a welding member placing process inwhich a welding member 200 (FIG. 3) is placed on the core wire 110, anda terminal forming process in which the core wire 110 of theterminal-forming target portion 130 is configured to form a terminalalong with the welding member 200. In this method of manufacturing theterminal-formed electric wire, as illustrated in FIG. 4, the weldingmember placing process is performed (step S1), and the terminal formingprocess is then performed (step S2).

The welding member 200 is a member formed of metal having a meltingpoint lower than that of metal of a base material of the strands 110 a.For example, if the base material of the strand 110 a is aluminum oraluminum alloy, the welding member 200 may be formed of zinc having amelting point lower than that of the base material.

Since this welding member 200 is more easily melted than the strand 110a, it can intrude into gaps between the strands 110 a along an oxidefilm on the surface of the base material of the strands 110 a even whenthe strands 110 a are not perfectly melted during the terminal formingprocess (there is a possibility that an oxide film having a highermelting point than that of the base material is formed on the surface ofthe base material of the strands 110 a formed of aluminum or aluminumalloy). For this reason, this welding member 200 can strongly connectthe gaps of the solidified strands 110 a even when the base material ofthe strands 110 a is not perfectly melted. In addition, it is possibleto reduce or remove a cavity between the solidified strands 110 a.Therefore, in the terminal portion 130A, it is possible to increase astrength (such as a bonding strength or a tensile strength) by placingthe welding member 200 on the core wire 110 of the terminal-formingtarget portion 130 in advance, compared to a case where only the corewire 110 is formed as a terminal. In addition, since a gap between thestrands 110 a is filled with the melted welding member 200, if thedesired terminal shape is an eyelets type, a seat surface for theterminal portion 130A, which is configured to suppress a recess causedby such as collapse is formed. For this reason, using this eyelets typeterminal portion 130A makes it possible to suppress a decrease of anaxial force after screw fastening to a counterpart electric connectiontarget and maintain a fastening force with the electric connectiontarget (that is, electric connection state).

Here, as described above, the oxide film is formed on the surface of thebase material of the strands 110 a regardless of the type of the basematerial. In the terminal forming process, if the oxide film is formedon the strands 110 a, the welding member 200 being melted intrudes fromthe gap of the oxide film cracked, for example, by thermal expansion orthe like, so that the melted base material of the strand 110 a and themelted welding member 200 form a solid solution, and the oxide film ofthe strand 110 a rises up. As a result, in the terminal portion 130A, itis possible to increase a bonding area of the strands 110 a and improveits strength (such as a bonding strength or a tensile strength) byplacing the welding member 200 in the core wire 110 of theterminal-forming target portion 130 in advance even when the oxide filmis formed on the strand 110 a. In addition, in the terminal portion130A, since the oxide film can be easily removed, it is possible toreduce a resistance (film resistance), compared to a case where only thecore wire 110 is formed.

In this manner, in the method of manufacturing the terminal-formedelectric wire according to the present embodiment, the welding member200 is employed to form a desired terminal portion 130A. In thefollowing description, a specific example of the method of manufacturingthe terminal-formed electric wire will be described by focusing on thewelding member placing process and the terminal forming process.

In the welding member placing process, at least one welding member 200is placed for the core wire 110 of at least the terminal-forming targetportion 130 of the electric wire 100.

In the welding member placing process according to the presentembodiment, the welding member 200 is placed to interpose the core wire110.

For example, here, it is assumed that an eyelets type terminal portion130A is formed in the terminal forming process. In the case of thisterminal shape, the terminal-forming target portion 130 is formed in atemporary shape of the terminal portion 130A, and the welding memberplacing process is then performed for the terminal-forming targetportion 130 having the temporary shape. Then, the terminal formingprocess is performed.

First, a process for forming the temporary shape of the terminal portion130A will be described. In this formation process, a bending process forthe terminal-forming target portion 130 and a pre-molding process forthe terminal-forming target portion 130 subjected to the bending processare performed.

In order to perform this formation process, if no core wire exposedportion is formed in the process of manufacturing the electric wire 100,the covering 120 is stripped off in that place to form the core wireexposed portion (the exposed portion of the core wire). Then, thetemporary shape formation process is performed for the terminal-formingtarget portion 130 in this core wire exposed portion. If the core wireexposed portion is formed in the process of manufacturing the electricwire 100, the temporary shape formation process is performed for theterminal-forming target portion 130 in the core wire exposed portion.

In this temporary shape formation process, the terminal-forming targetportion 130 exposed without a covering 120 is bent in a ring shape, andpress-molding is performed for this ring-shaped terminal-forming targetportion 130, so that the terminal-forming target portion 130 is formedin a temporary shape of a desired eyelet terminal type. Although notillustrated in detail, in this pre-molding process, a first molding die11 provided with a trench 11 a and a second molding die 12 provided witha protrusion 12 a insertable into the trench 11 a are used (FIGS. 5 and6). The first and second molding dies 11 and 12 are molds formed of, forexample, metal. The protrusion 12 a is inserted into the trench 11 a asthe dies approach each other. The protrusion 12 a is removed from thetrench 11 a as they are separated. Both the trench 11 a and theprotrusion 12 a are shaped to match the desired eyelets terminal type.In this pre-molding process, the ring-shaped terminal-forming targetportion 130 is set in the trench 11 a in an insertion state. Inaddition, in this pre-molding process, by approaching the first andsecond molding dies 11 and 12, the ring-shaped terminal-forming targetportion 130 is crushed between the trench 11 a and the protrusion 12 ato form the temporary shape of the desired eyelets terminal type (FIG.3).

Then, this method of manufacturing the terminal-formed electric wireadvances to the welding member placing process. In this example of thewelding member placing process, a pair of welding members 200A having aflat ring shape are used as the welding member 200, and the ring-shapedterminal-forming target portion 130 having the temporary shape isinterposed between the pair of welding members 200A in a coaxial manner(FIGS. 3 and 7).

Then, this method of manufacturing the terminal-formed electric wireadvances to the terminal forming process. In the terminal formingprocess, a pair of electrodes having a shape corresponding to thedesired terminal shape is employed. In this terminal forming process,the exposed terminal-forming target portion 130 is interposed betweenthe pair of electrodes having a shape corresponding to the desiredterminal shape. An electric current flows to the pair of electrodeswhile the terminal-forming target portion 130 is pressed by the pair ofelectrodes, so that at least the welding member 200 of theterminal-forming target portion 130 is melted. Then, in this terminalforming process, the melted metal is solidified by stopping the electriccurrent flowing to the pair of electrodes. As a result, theterminal-forming target portion 130 formed as a terminal portion 130Ahaving a desired terminal shape. That is, this terminal forming processcan be classified into a melting process and a solidifying process forthe terminal-forming target portion 130. In this terminal formingprocess, resistance welding is performed using the first and secondelectrodes 20 and 30 as the pair of electrodes (FIGS. 8 to 11).

Although not illustrated in detail, the first and second electrodes 20and 30 form a press electrode configured to shape the terminal-formingtarget portion 130 into the terminal portion 130A of the desired eyeletsterminal type by interposing the ring-shaped terminal-forming targetportion 130 (obtained by forming the temporary shape of the desiredeyelets terminal type) between the first and second electrodes 20 and 30and performing pressurizing, heating, and cooling for theterminal-forming target portion 130 in this state. The first and secondelectrodes 20 and 30 have electrical conductivity and high thermalconductivity, and are constituted of a material having a melting pointhigher than that of the base material of the strand 110 a. The first andsecond electrodes 20 and 30 are driven such that at least one of themapproaches or separates from the counterpart electrode. The first andsecond electrodes 20 and 30 are placed such that corresponding pressers21 and 31 described below face each other depending on the drivingdirection.

The first electrode 20 has the presser 21 coming into contact with onering surface side of the ring-shaped terminal-forming target portion 130of the temporary shape (in this example, one of the ring surfaces of oneof the welding members 200A). The presser 21 has a ring-shaped pressingsurface 21 a capable of covering a ring surface 130 a of theterminal-forming target portion 130 approximately in a coaxial mannerand a circular column portion 21 b placed coaxially with the pressingsurface 21 a (FIG. 10). The pressing surface 21 a is a flat plane formedto have an axial direction corresponding to a driving direction and isformed to be larger than the ring surface 130 a in a radial outer sideand smaller than the ring surface 130 a in a radial inner side. In theterminal forming process, the ring surface 130 a comes into contact withthis pressing surface 21 a. The circular column portion 21 b is a partprotruding to the second electrode 30 side relative to the pressingsurface 21 a in the driving direction and is inserted into a radialinner space of the terminal-forming target portion 130. This circularcolumn portion 21 b sets a height along the driving direction so as notto come into contact with the second electrode 30 while the pressingsurface 21 a and the ring surface 130 a come into contact with eachother. In this example, the ring-shaped terminal-forming target portion130 of the temporary shape is set on the first electrode 20 by arrangingthe first electrode 20 such that the pressing surface 21 a is directedupward, and the ring surface 130 a is placed on the pressing surface 21a.

The second electrode 30 has the presser 31 coming into contact with theother ring surface side of the ring-shaped terminal-forming targetportion 130 of the temporary shape (in this example, one of the ringsurfaces of the other welding member 200A). The presser 31 has aring-shaped pressing surface 31 a capable of covering a ring surface 130b of the terminal-forming target portion 130 approximately in a coaxialmanner and a circular column portion 31 b placed coaxially with thepressing surface 31 a (FIG. 10). Similar to the pressing surface 21 a ofthe first electrode 20, the pressing surface 31 a is a flat plane formedto have an axial direction corresponding to the driving direction and isformed to be larger than the ring surface 130 b in a radial outer sideand smaller than the ring surface 130 b in a radial inner side. Thispressing surface 31 a is placed to face the pressing surface 21 a of thefirst electrode 20 in the driving direction and in a coaxial manner. Inthe terminal forming process, the ring surface 130 b comes into contactwith the pressing surface 31 a. The circular column portion 31 b is apart protruding to the first electrode 20 side relative to the pressingsurface 31 a in the driving direction and is inserted into a radialinner space of the terminal-forming target portion 130. This circularcolumn portion 31 b sets a height along the driving direction so as notto come into contact with the first electrode 20 while the pressingsurface 31 a and the ring surface 130 b come into contact with eachother. In this example, the second electrode 30 approaches the firstelectrode 20 or separates from the first electrode 20 by arranging thesecond electrode 30 such that the pressing surface 31 a is directeddownward and driving the second electrode 30.

In this terminal forming process, after the ring-shaped terminal-formingtarget portion 130 of the temporary shape is set on the first electrode20, the second electrode 30 moves to the first electrode 20, so that thering surfaces 130 a and 130 b of the terminal-forming target portion 130are interposed between the pressing surfaces 21 a and 31 a of the firstand second electrodes 20 and 30. In addition, each of the circularcolumn portions 21 b and 31 b is inserted into a radial inner space ofthe terminal-forming target portion 130 (FIG. 10). Between the first andsecond electrodes 20 and 30, the ring surfaces 130 a and 130 b of theterminal-forming target portion 130 are pressed by the pressing surfaces21 a and 31 a, respectively, by a pressing force set or designated tocorrespond to the core wire 110 and the welding member 200 of thering-shaped terminal-forming target portion 130 of the temporary shape.

In this terminal forming process, the processing flow advances to themelting process in this pressed state. In the melting process, the firstand second electrodes 20 and 30 are electrically conducted at aconduction current value and a conduction time set or designated tocorrespond to the core wire 110 and the welding member 200. As a result,in this melting process, at least the welding member 200 is melted.

In this terminal forming process, electrical conduction stops when theset or designated conduction time elapses, and the processing flowadvances to the solidification process. In the solidification process,the pressing state for the terminal-forming target portion 130 betweenthe first and second electrodes 20 and 30 is maintained until thesolidification time set or designated to correspond to the core wire 110and the welding member 200 elapses. In this solidification process, theelectric conduction stops, and cooling of the terminal-forming targetportion 130 starts. In addition, solidification of the melted metal ofthe terminal-forming target portion 130 starts. In this solidificationprocess, the solidification of the melted metal is terminated until thesolidification time elapses, so that the terminal-forming target portion130 of the temporary shape is formed as the terminal portion 130A. Inthis terminal forming process, when the solidification time elapses, thesecond electrode 30 is separated from the first electrode 20 by drivingthe second electrode 30 (FIG. 11).

In the terminal forming process, the terminal-forming target portion 130of the electric wire 100 is formed in this manner.

As described above, in the method of manufacturing the terminal-formedelectric wire according to the present embodiment, the welding member200 (200A) melted earlier than the core wire 110 can be entered the gapbetween the strands 110 a by arranging the welding member 200 (200A)having a melting point lower than that of the core wire 110 in the corewire 110 of the terminal-forming target portion 130 in advance.Therefore, even when the strands 110 a are not perfectly melted in theterminal forming process, the melted welding member 200 (200A) canconnect the strands 110 a as it is solidified. In addition, in thismethod of manufacturing the terminal-formed electric wire, the gapbetween the strands 110 a can be filled with the melted welding member200 (200A) even when the strands 110 a are not perfectly melted in theterminal forming process. Therefore, it is possible to reduce or removea cavity between the solidified strands 110 a. In this manner, in themethod of manufacturing the terminal-formed electric wire according tothe present embodiment, it is possible to form the terminal portion 130Ahaving a desired shape or strength, compared to a case where only thecore wire 110 is fitted. Furthermore, in the method of manufacturing theterminal-formed electric wire according to the present embodiment, theterminal-forming target portion 130 can be formed using the weldingmember 200 (200A) having a melting point lower than that of the corewire 110. Therefore, it is not necessary to increase the conductioncurrent value or delay the conduction time for the pair of electrodesunlike the background art. For this reason, in the method ofmanufacturing the terminal-formed electric wire, it is possible tosuppress an increase of the manufacturing cost necessary for theterminal forming.

First Modification

In the present modification, compared to the embodiment, the weldingmember placing process is changed as described below. Depending on thischange, other processes are also appropriately changed.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, a plurality of strands 110 a ofthe terminal-forming target portion 130 are divided into a plurality ofstrand groups, and the welding members 200 are placed for this strandgroup. For this reason, in the method of manufacturing theterminal-formed electric wire, a strand dividing process in which thestrands are divided into the strand groups is provided. In the weldingmember placing process according to the present modification, the strandgroups and the welding members 200 are placed alternately.

First, in the method of manufacturing the terminal-formed electric wireaccording to the present modification, a strand dividing process isperformed for the exposed terminal-forming target portion 130, and thetemporary shape formation process (including the bending process and thepre-molding process) is then performed. In this example, theterminal-forming target portion 130 is divided into two strand groups111 and 112, and each strand group 111 and 112 is bent in a ring shape,so that the ring-shaped strand groups 111 and 112 are formed into thering-shaped strand groups 111 and 112, respectively, of the temporaryshape (FIG. 12). That is, in the temporary shape formation process ofthe present modification, the terminal-forming target portion 130 isformed as a molded body corresponding to the temporary shape of thedesired eyelets terminal type for each divided strand group 111 and 112.Each ring-shaped strand group 111 and 112 of the temporary shape isplaced approximately in a coaxial manner.

Then, in this method of manufacturing the terminal-formed electric wire,the processing flow advances to the welding member placing process.Similar to the embodiment mentioned above, in this welding memberplacing process, a ring-shaped and flat welding member 200A is used asthe welding member 200. The number of welding members 200A is determineddepending on an installation place to the ring-shaped strand groups 111and 112 of the temporary shape.

For example, when the welding member 200A is placed between thering-shaped strand groups 111 and 112 of the temporary shape, a singlewelding member 200A is prepared. In this case, the welding member 200Ais placed between the strand groups 111 and 112 approximately in acoaxial manner, and the welding member 200A is interposed between thestrand groups 111 and 112 (FIG. 13). In addition, the welding members200A may be placed to interpose any one of the ring-shaped strand groups111 and 112 of the temporary shape approximately in a coaxial manner(FIG. 14). In this case, a pair of welding members 200A are prepared. InFIG. 14, the strand group 111 is interposed between the pair of weldingmembers 200A. In addition, the welding members 200A may be placedinterpose each of the strand groups 111 and 112 for each ring-shapedstrand group 111 and 112 of the temporary shape approximately in acoaxial manner (FIG. 15). In this case, two welding members 200A may beinterposed, or only one welding member 200A may be interposed betweenthe strand groups 111 and 112. In FIG. 15, one welding member 200A isinterposed between the strand groups 111 and 112.

Then, in the method of manufacturing the terminal-formed electric wire,the processing flow advances to the terminal forming process. In thisterminal forming process, terminal forming is performed for thering-shaped terminal-forming target portion 130 of the temporary shapein which the strand groups 111 and 112 and the welding member 200A arestacked. This terminal forming process is performed similar to theembodiment, and will not be described here.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, it is possible to obtain the sameeffects as those of the method of manufacturing the terminal-formedelectric wire of the embodiment by arranging the welding member(s) 200(200A) in such positional relationships in advance.

Second Modification

In the present modification, compared to the embodiment, the weldingmember placing process is changed as described below. Depending on thischange, other processes are also appropriately changed.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, the welding member 200 isinserted between a plurality of strands 110 a in the welding memberplacing process. This welding member 200 may have any shape as long asit can be inserted between the strands 110 a. If this welding memberplacing process is included in a manufacturing process of the electricwire 100, this welding member placing process may be performed beforethe terminal forming process and after the manufacturing process of theelectric wire 100.

If the welding member placing process is included in the manufacturingprocess of the electric wire 100, for example, a wire welding member200B having the same shape as that of the strand 110 a is employed asthe welding member 200 (in the left half of FIG. 16), and this weldingmember 200B is bound with a plurality of strands 110 a to form a corewire 110 provided with the welding member 200B (in the right half ofFIG. 16). That is, in this case, the welding member placing process isperformed in the manufacturing process of the core wire 110. In thiscase, in the manufacturing process of the electric wire 100, a covering120 is formed after the manufacturing of the core wire 110 orsimultaneously with the manufacturing of the core wire 110. In thiscase, if the core wire exposed portion is not formed in themanufacturing process of the electric wire 100, the covering 120 of thatlocation is stripped off to form the core wire exposed portion beforethe temporary shape formation process is progressed. If the core wireexposed portion is formed in the manufacturing process of the electricwire 100, the processing flow advances to the temporary shape formationprocess. As a result, in this electric wire 100, the welding member 200Bis inserted between a plurality of strands 110 a at least in theterminal-forming target portion 130 when the temporary shape formationprocess is performed (FIG. 17). Note that, in each drawing, forconvenient description purposes, cross hatching is applied to thewelding member 200B, and this welding member 200B is placed in the outerside of a bundle of the strands 110 a.

Meanwhile, if the welding member placing process is performed after themanufacturing process of the electric wire 100 and before the terminalforming process, the processing flow is different depending on whetheror not the core wire exposed portion is formed in the electric wire 100after the manufacturing process of the electric wire 100. If the corewire exposed portion is not formed in the manufacturing process of theelectric wire 100, the covering 120 in that location is stripped off,and the core wire exposed portion is formed. Then, the processing flowadvances to the welding member placing process for the terminal-formingtarget portion 130 of this core wire exposed portion. In contrast, ifthe core wire exposed portion is formed in the manufacturing process ofthe electric wire 100, the processing flow advances to the weldingmember placing process for the terminal-forming target portion 130 ofthis core wire exposed portion. In this case, in the welding memberplacing process, a wire-like welding member 200C having a length equalto or longer than that of the terminal-forming target portion 130 isused as the welding member 200 (FIG. 18). Here, the welding member 200Cis formed to be longer than the core wire exposed portion. In thiswelding member placing process, the welding member 200C is insertedbetween a plurality of strands 110 a at least in the terminal-formingtarget portion 130 such that a longitudinal direction of the weldingmember 200C follows an extending direction of each strand 110 a (FIG.17). Note that, in each drawing, for convenient description purposes,cross hatching is applied to the welding member 200C, and this weldingmember 200C is placed in an outer side of each bundle of the strands 110a.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, the temporary shape formationprocess (including the bending process and the pre-molding process) isperformed for the terminal-forming target portion 130 where the weldingmember 200 (200B or 200C) is inserted. For this reason, in thering-shaped terminal-forming target portion 130 of the temporary shapesubjected to this formation process, the welding member 200 (200B and200C) is mixed with a plurality of strands 110 a (FIG. 19). In thismethod of manufacturing the terminal-formed electric wire, the terminalforming process is performed for the ring-shaped terminal-forming targetportion 130 of the temporary shape where the welding member 200 (200B or200C) is mixed. The temporary shape formation process and the terminalforming process are performed similar to the embodiment, and will not bedescribed here. Note that, in the drawings, for convenient descriptionpurposes, cross hatching is applied to the welding member 200 (200B or200C), and this welding member 200 (200B or 200C) is placed in an outerside of each bundle of the strands 110 a.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, it is possible to obtain the sameeffects as those of the method of manufacturing the terminal-formedelectric wire of the embodiment by inserting the welding member 200(200B or 200C) between the strands 110 a in advance.

Third Modification

In the present modification, compared to the embodiment, the weldingmember placing process is changed as described below. Depending on thischange, other processes are also appropriately changed.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, the welding member 200 is woundaround the core wire 110 in the welding member placing process. In thismethod of manufacturing the terminal-formed electric wire, a weldingmember 200D, for example, having a tape shape or a foil shape isemployed as the welding member 200 (FIG. 20). If this welding memberplacing process is included in the manufacturing process of the electricwire 100, the welding member placing process may be performed after themanufacturing process of the electric wire 100 and before the terminalforming process.

If the welding member placing process is included in the manufacturingprocess of the electric wire 100, the welding member 200D is woundaround the core wire 110 formed by binding a plurality of strands 110 a.In addition, in this manufacturing process of the electric wire 100, thecovering 120 is formed on the core wire 110 where the welding member200D is wound. In this case, if the core wire exposed portion is notformed in the manufacturing process of the electric wire 100, thecovering 120 in that location is stripped off to form the core wireexposed portion before the temporary shape formation process. If thecore wire exposed portion is formed in the manufacturing process of theelectric wire 100, the processing flow advances to the temporary shapeformation process. As a result, in this electric wire 100, the weldingmember 200D is wound around the core wire 110 of at least theterminal-forming target portion 130 when the temporary shape formationprocess is performed (FIG. 21).

Meanwhile, if the welding member placing process is performed after themanufacturing process of the electric wire 100 and before the terminalforming process, the processing flow is different depending on whetheror not the core wire exposed portion is formed in the electric wire 100after the manufacturing process of the electric wire 100. If the corewire exposed portion is not formed in the manufacturing process of theelectric wire 100, the covering 120 in that location is stripped off,and the core wire exposed portion is formed. Then, the processing flowadvances to the welding member placing process for the terminal-formingtarget portion 130 of this core wire exposed portion. In contrast, ifthe core wire exposed portion is formed in the manufacturing process ofthe electric wire 100, the processing flow advances to the weldingmember placing process for the terminal-forming target portion 130 ofthis core wire exposed portion. In this welding member placing process,the welding member 200D is wound around the core wire 110 formed bybinding a plurality of strands 110 a in at least the terminal-formingtarget portion 130 (FIG. 21).

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, the temporary shape formationprocess (including the bending process and the pre-molding process) isperformed for the terminal-forming target portion 130 where the weldingmember 200 (200D) is wound. For this reason, in the ring-shapedterminal-forming target portion 130 of the temporary shape subjected tothis formation process, the welding member 200 (200D) exists on thesurface of the core wire 110 (FIG. 22). In this method of manufacturingthe terminal-formed electric wire, the terminal forming process isperformed for the ring-shaped terminal-forming target portion 130 of thetemporary shape where the welding member 200 (200D) exists. Thetemporary shape formation process and the terminal forming process areperformed similar to the embodiment, and will not be described here.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, it is possible to obtain the sameeffects as those of the method of manufacturing the terminal-formedelectric wire of the embodiment by winding the welding member 200 (200D)around the core wire 110 in advance.

Fourth Modification

In the present modification, compared to the embodiment, the weldingmember placing process is changed as described below. Depending on thischange, other processes are also appropriately changed.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, for example, a welding member200E having a powder shape is prepared in a container 40 as the weldingmember 200, and the welding member 200E is applied to the core wire 110in the welding member placing process (FIG. 23). This welding memberplacing process is performed after the bending process of the embodimentor after the pre-molding process of the embodiment.

If the welding member placing process is performed after the bendingprocess, the powder-like welding member 200E is applied to at least thering-shaped terminal-forming target portion 130 in the welding memberplacing process. In this case, then, the processing flow advances to thepre-molding process, so that the ring-shaped terminal-forming targetportion 130 where the powder-like welding member 200E is attached ismolded to the ring-shaped terminal-forming target portion 130 of thetemporary shape. Meanwhile, if the welding member placing process isperformed after the pre-molding process, the powder-like welding member200E is applied to at least the ring-shaped terminal-forming targetportion 130 of the temporary shape in the welding member placingprocess. In this case, then, the processing flow advances to theterminal forming process. As a result, the powder-like welding member200E is attached on the ring-shaped terminal-forming target portion 130of the temporary shape subjected to the pre-molding process (FIG. 24).The temporary shape formation process (including the bending process andthe pre-molding process) is performed similar to the embodiment, andwill not be described here.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, the terminal forming process isperformed for the terminal-forming target portion 130 of the temporaryshape, that is, the terminal-forming target portion 130 where thewelding member 200 (200E) is attached (FIG. 24). The terminal formingprocess is performed similar to the embodiment, and will not bedescribed here.

In the method of manufacturing the terminal-formed electric wireaccording to the present modification, it is possible to obtain the sameeffects as those of the method of manufacturing the terminal-formedelectric wire of the embodiment by applying the welding member 200(200E) to the core wire 110 in advance.

In the method of manufacturing the terminal-formed electric wireaccording to the embodiment, the welding member having a melting pointlower than that of the core wire is placed in the core wire of theterminal-forming target portion in advance, so that the welding membermelted in advance of the core wire can intrude into a gap between thestrands in the terminal forming process. For this reason, in this methodof manufacturing the terminal-formed electric wire, even when the strandis not perfectly melted in the terminal forming process, the meltedwelding member can bind the strands as the melted welding member issolidified. In addition, in this method of manufacturing theterminal-formed electric wire, the melted welding member can fill a gapbetween strands even when the strand is not perfectly melted in theterminal forming process. Therefore, it is possible to reduce or removea cavity between the solidified strands. In this manner, in the methodof manufacturing the terminal-formed electric wire according to theembodiment, it is possible to form the terminal-forming target portionas a terminal portion having a desired terminal shape, compared to acase where only the core wire is formed.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. A method of manufacturing a terminal-formedelectric wire, the method comprising: a welding member placing processin which at least one welding member formed of metal having a meltingpoint lower than that of a plurality of metal strands included in a corewire is arranged to the core wire of at least a terminal-forming targetportion of an electric wire; and a terminal forming process in which theexposed terminal-forming target portion is interposed between a pair ofelectrodes having a shape corresponding to a desired terminal shape, atleast the welding member in the terminal-forming target portion ismelted by electrically conducting the pair of electrodes while pressingthe terminal-forming target portion with the pair of electrodes, andmelted metal is solidified by stopping electric conduction to the pairof electrodes, so that the terminal-forming target portion is formed asa terminal portion having the terminal shape.
 2. The method ofmanufacturing the terminal-formed electric wire according to claim 1,wherein in the welding member placing process, the welding member isarranged to interpose the core wire.
 3. The method of manufacturing theterminal-formed electric wire according to claim 1, further comprising:a strand dividing process in which the plurality of strands of theterminal-forming target portion are divided into a plurality of strandgroups, wherein in the welding member placing process, the strand groupsand welding members are arranged alternately.
 4. The method ofmanufacturing the terminal-formed electric wire according to claim 1,wherein in the welding member placing process, the welding member isinserted between the plurality of strands.
 5. The method ofmanufacturing the terminal-formed electric wire according to claim 1,wherein in the welding member placing process, the welding member iswound around the core wire.
 6. The method of manufacturing theterminal-formed electric wire according to claim 1, wherein in thewelding member placing process, a powder-like welding member is appliedto the core wire.